Auxiliary-bicycle torsion sensing and large gear plate minimization apparatus

Abstract

An auxiliary-bicycle torsion sensing and large gear plate minimization apparatus, arranged in transmission apparatus of an auxiliary-bicycle, includes a sun gear, a unidirectional device, a planet gear set and a sensing device. The sun gear of planet gear set is connected to the crank axle of auxiliary-bicycle and driven directly with it. The stepping power of crank axle is output to the large gear plate of auxiliary-bicycle through the transmission of sun gear, planet gear and unidirectional device. Also, one side of swing arm, used for pivotally arranging sun gear and planet gear, is arranged with the sensing device. When crank axle is rotated by the stepping force of rider, the swing arm will generate a rotation torsion, and sensing device senses the torsion value to control the power output of driving motor. The present invention has the characteristics of simple structure, low manufacture cost, more accurate sensitivity, and further instant changeable rotation ratio between crank axle and large gear plate to meet the object of broader application, such as the outlook beautification due to the minimization of large gear plate.

What is claimed is:  
     
       1. An auxiliary-bicycle torsion sensing and large gear plate minimization apparatus, said apparatus being engaged with a transmission apparatus of auxiliary-bicycle, said transmission apparatus comprising at least a crank axle, a gear plate and a speed-variation gear set; by rotating the crank axle, power output of a driving apparatus of said auxiliary-bicycle can be controlled; the power output driving the gear plate to rotate through the transmission of transmission apparatus; said auxiliary-bicycle torsion sensing and large gear plate minimization apparatus comprising: 
       a sun gear, which is fixed to the crank axle and driven together with it to rotate;  
       a planet gear set, which at least includes a swing arm and a first planet gear; the swing arm pivotally engaged with the crank axle and is capable of rotating about the crank axle in a limited degree; the first planet gear is pivotally engaged with the swing arm and driven together with the sun gear to rotate; the first planet gear is driven to rotate by the rotation of crank axle and further make the swing arm generating a rotation torsion in the same rotation direction which is same as that of sun gear; and  
       a sensing apparatus, which contacts with one side of the swing arm and may sense the rotation torsion of the swing arm, and generates a sensing signal to control the power output of driving apparatus.  
     
     
       2. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 1 , further comprising: 
       a unidirectional device, which is connected to the gear plate and may proceed a single direction transmission; and  
       a second planet gear, which is arranged at the planet gear set and driven to rotate together with the second planet gear; the second planet gear is driven together with the unidirectional device; the direction of unidirectional transmission makes the second planet gear may drive the gear plate to rotate; however the gear plate can not drive the second planet to rotate.  
     
     
       3. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 2 , wherein the speed-variation gear set connects and drives the gear plate through the transmission of the unidirectional device; the speed-variation gear set may drive the gear plate to rotate through the transmission of unidirectional device; however the gear plate can not drive the speed-variation gear set to rotate. 
     
     
       4. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 2 , wherein the unidirectional device is a unidirectional ratchet device. 
     
     
       5. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 2 , wherein the speed-variation gear set is a speed-reduction gear set. 
     
     
       6. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 2 , wherein the speed-variation gear set is comprised of several matching together multi-level gears. 
     
     
       7. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 2 , wherein it further includes a medium gear and a ring gear; the medium gear is matched with the second planet gear; the ring gear is then also matched with the medium gear and the unidirectional device. 
     
     
       8. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 1 , wherein the driving apparatus is an electric driving motor. 
     
     
       9. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 1 , wherein the sensing apparatus includes a pushing pillar and a stress sensor; one end of the pushing pillar pushes against the swing arm; another end is then connected with the stress sensor; the pushing pillar may transfer the rotation torsion of swing arm to the stress sensor. 
     
     
       10. The auxiliary-bicycle torsion sensing and large gear plate minimization apparatus according to the  claim 9 , wherein the sensing apparatus further includes a replacement element and a pushing block; the pushing block pushes against the swing arm; the replacement element connects to the pushing pillar and provides an elastic force to make the pushing pillar maintain a predetermined position under the state of no external force.